Download Type of Bonding

I. Intramolecular and Intermolecular Forces : Attractive
Type of Interaction
Covalent :
Metallic :
Ionic :
• ion-ion
Polar Interactions :
• charge-dipole
• dipole-dipole
• hydrogen bonding
VDW
Classificatio
n
Primary or
Chemical Bonds :
• usually characterized as
individually “strong”
• outer orbital ecooperatively shared
between two or more
atoms so that discrete
nature of atoms is lost
• quantum mechanical in
origin
Secondary or
Physical
Interactions :
• usually characterized as
individually “weak”
• no e- sharing, more
subtle attraction between
(+) and (-) charges,
discrete nature of atoms
preserved
• typically exhibits :
• lack of specificity
• lack of directionality
• lack of stoichiometry
• charge-nonpolar (induced or
instantaneous dipole)
• dipole-nonpolar (induced dipole)
Dispersion or London
Interactions :
Special
Interactions :
• not really true
“bonds”
• non-directional
Entropic Elasticity :
e- e-
• only metals atoms are involved
• e- are completely delocalized and
mobile throughout entire material
• non-directional
• coulombic in origin, occurs
between oppositely charged species
• electron transfer from one atom
to another
• force between an ion and a
dipole or two dipoles where the (+)
charge attracts the (-) charge
(purely electrostatic)
• H-bonding : a special type of
dipole-dipole interaction that
results from the bonding
between a H atom which is
partially (+) charged and a
highly electronegative atom
such as O, F, N, Cl,
(directional)
• the (+) nucleus of a nonpolar
atom attracts the (-) charged
electrons of another nonpolar atom
resulting in instantaneous, induced,
dipoles and fluctuating electron
clouds
• quantum mechanical in origin
(*also called charge-fluctuation,
electrodynamic, induced-dipoleinduced dipole forces)
• nonpolar-nonpolar
Schematic
• e- are localized
• directional (i.e. oriented at welldefined angles to each other)
• an ion or dipole in the vicinity of
a nonpolar atom or molecule
causes instantaneous polarization
and electrostatic attraction
Polarization
Interactions :
Hydrophobic :
Characteristics
• attraction between nonpolar
molecules in aqueous solution
caused by their inability to form Hbonds with HOH so as to
minimize the disruption of Hbonds in HOH
• entropy-driven
• attractive, recoiling force
produced via extensional
deformation macromolecules
ee- + + + ee
e- e- - e+ + e-+ ee- e-
cation
anion
+
-
+
δ-
δ-
δ+
δ-
δ+
H
H
O
H
H
O
O
H
δ+
H
δ+
δ+
δ-
+
H
H
O
δ-
δ+
δ-
δ+
δ-
δ+
δ-
δ+
δ-
δ+
H
H
O
H
H
H
O
C
O
H
H
C
H H
H
C
H
H
H
H
O
H
O
H
H
H
O
H
H
H
O
H
H
O
H
H
II. Intramolecular and Intermolecular Forces : Repulsive
Type of Interaction
Characteristics
Exchange, Hard-Core,
or Steric Repulsion :
• repulsion due to overlap of electron clouds
according to Pauli Exclusion Principle, as well as
repulsion of (+) charged nuclei
• quantum mechanical in origin
Born Repulsion :
• electrostatic repulsion between similarly charged
ions
Hydrophilic :
• repulsion of two hydrophilic molecules in
aqueous solution in order to maximize H-bonding
to water
Entropic Elasticity :
• repulsive force produced via compression of longchained, flexible macromolecules
Diffuse Counterion
Electrical Double
Layer :
• repulsive osmotic force between two charged surface
due to overlap of diffuse counterion electrical double
layers
Steric Repulsion
(Polymers) :
• osmotic pressure originates from solvent translational
entropy and intrachain excluded volume due to shortrange monomer-solvent affinity and/or monomermonomer repulsion.
Schematic
e
-+
+
e
+
+